In a multi-link suspension, wheels are joined to a central subframe of a vehicle by means of a plurality of arms linking or joining the wheel stub axle with said subframe. Such suspensions are the object of recent technological developments made in the automotive industry. The main reason for using this suspension lies in the great rigidity it provides to the vehicle laterally, successfully preventing the well-known oversteer phenomenon. It also provides greater directional stability in the direction of travel and allows absorbing a high percentage of vibrations and noise. Multi-link suspensions therefore provide the vehicle with greater maneuverability, safety and superior comfort while travelling.
Within such suspensions, the suspension arm is a kinematic element the function of which is to statically and dynamically define the relative position of the wheel with respect to the frame of the vehicle while at the same time transmitting part of the forces of the wheel to the bodywork, and vice versa.
Today, there is large variety of suspension arms which are obtained by means of different processes, among which stamping sheet metal, forging or smelting pieces of aluminum or steel and welding bushings to tubes must be pointed out. All the cases require achieving sufficient rigidity regardless of the operating temperature.
In this sense, U.S. Pat. No. 8,616,570-B2 describes a suspension arm the cross-section of which is open and has the shape of the number Pi (π). Given its open section, this suspension arm is vulnerable to tensile, compressive and torsional stresses, as well as in its fatigue behavior. However, this suspension arm requires a specific final geometry or shape given that in addition to acting as a joint between the stub axle and subframe, it also has the function of acting as a link with other tertiary elements such as the case of the damper, which causes it to have this complex final shape, involving a large number of processes for manufacture, and therefore having a high cost.
Likewise, U.S. Pat. No. 7,850,182-B2 describes a suspension arm the cross-section of which is formed by a main cavity in the center flanked by other two side cavities located on the left and on the right. For this arm to have a shape that allows avoiding other elements of the bodywork, a variable curvature extruding process is necessary. The arm comprises an upper plate or base with cantilevered portions the purpose of which is to support tertiary elements such as the damper, like in the patent mentioned in the preceding paragraph.